Field
Exemplary embodiments of the present disclosure relate to a method and system to dry crack-free and high strength skin on a porous ceramic body.
Discussion of the Background
After-treatment of exhaust gas from internal combustion engines may use catalysts supported on high-surface area substrates and, in the case of diesel engines and some gasoline direct injection engines, a catalyzed filter for the removal of carbon soot particles. Filters and catalyst supports in these applications may be refractory, thermal shock resistant, stable under a range of pO2 conditions, non-reactive with the catalyst system, and offer low resistance to exhaust gas flow. Porous ceramic flow-through honeycomb substrates and wall-flow honeycomb filters (generically referred to herein as honeycomb bodies) may be used in these applications.
Particulate filters and substrates may be difficult to manufacture to external dimensional requirements set by original equipment manufacturers (OEMs) and the supply chain due to drying and firing shrinkage during manufacturing. Consequently, ceramic cement may be used to form an exterior skin of a honeycomb body which has been machined or “contoured” to a desired dimension. As used herein, the term “honeycomb body” includes single honeycomb monoliths and honeycomb bodies formed by multiple honeycomb segments that are secured together, such as by using a ceramic cement to form a monolith. Ceramic cement (skin cement) may be mixed and applied to a fired, contoured or segmented honeycomb body and the wet skin allowed to dry. The wet skin contains water (for example, 10%-35% by weight), and the skin needs to be dried prior to the formation of the final product (article). In some cases, the skin needs to be dried to greater than 98% dry (i.e., to having less than 2% of the original moisture content). The act or process of applying ceramic cement to the exterior of the honeycomb body is referred to herein as “skinning” the honeycomb body. A honeycomb body having skin disposed thereon is referred to herein as a “skinned” honeycomb body. As disclosed herein, contouring refers to grinding, machining, cutting, drilling, core drilling, etc. to a desired dimension.
Substrates and filters are currently skinned after firing and the skin dried using hot air in manufacturing. Skin drying cracks may arise during the skin drying process. Often skin drying cracks must be repaired by manual rework. The added labor and time for inspecting skinned honeycomb bodies and fixing of skin drying cracks leads to inefficiencies in product manufacturing. To avoid skin drying cracks a slow drying process is employed leading to additional product manufacturing inefficiencies.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the disclosure and therefore it may contain information that does not form any part of the prior art nor what the prior art may suggest to a person of ordinary skill in the art.